Lundy, Isle of Avalon

Sea -Levels 

Sea Levels in the South-West of Britain

'The coastline of Britain is fairly young in geological terms; as recently as 20,000 years ago the sea was thought to be about 100 to 150m below its present level. It was only after the most recent ice age, about 8,000 to 15,000 years ago, that sea levels rose to inundate low-lying land, forming the North Sea and English Channel. After this inundation, sea level rise slowed down and has remained relatively constant for the last 6,000 years.'  - Environment Agency

The effect of the flooding caused by the melting ice was exacerbated by the isotatic changes caused by post glacial rebound (PGR) as the weight of the ice sheet melted away. Nearly 10,000 years later this effect is still felt. Currently Scotland is rising at a rate of 1mm/year relative to the south of England.

The flooding from the melting ice must have happened relatively rapidly, while the PGR would probably have happened strongly at first and then more slowly, quite possibly with some violent seismological effects.

'Large, unpredictable fluctuations in sea level change that persist over decades are commonplace' [Douglas, 1992].

''If we turn to the Bristol Channel,' asserted the eminent geologist Sir Charles Lyell,' we find that both on the north and the south sides of it there are numerous remains of submerged forests; .. one of those at Porlock Bay ... extends far from the land. There is good reason to believe that there was once a woodland tract uniting Somersetshire and Wales, through the middle of which the ancient Severn flowed. This estuary of the Severn is in reality the largest 'drowned valley' in Britain. The outline of it has been somewhat modified by tidal action, and erosion continues at several sites.

'..geologists have found beaches which were raised dozens of feet above high water mark and some of these have later been returned to sea level. There a re also submerged forests to be found off  the coast of Cornwall.' --Mysterious Britain.

'According to data in 'The Subsidence of London' published in 1932, borings taken in the lower part of the Thames valley show that the land surfaces in late Neolithic times, about 2000 BC [the era of Stonehenge ], now lie between 60 and 70 feet below mean sea level. Even Roman remains under London lie about six feet below the Trinity high water mark. These discoveries mean that the whole geography of Britain was considerably different in ancient times when the great Megalithic monuments like Avebury, Stonehenge etc. were constructed.

' The Roman historian, Marcelinus, who lived in the fourth century of the Christian Era, described the swallowing up of 'a large island' in 'the Atlantic Sea'. This has always been identified as Atlantis, though it may equally be a record of the disintegration of islands on the coast of Britain, including parts of the Scillies, which probably went down during his lifetime.'  From Lost Lands and Sunken Cities

'The drowning of Mounts Bay is just one instance of a phenomenon visible all round the south - western promontory of Britain, once known as Dumnonia. In his 'Report on Cornwall', Sir Henry de la Beche remarked that 'submarine forests are so common that it is difficult not to find traces of them in the district at the mouths of all the numerous valleys which open upon the sea and are in any manner silted up'.

'All the evidence of geologists, antiquaries and archaeologists points to a permanent incursion of the sea having taken place at some time after the Roman period but before the end of the Middle Ages. The submerged coastline of the former Dumnonia, complete with its drowned valleys and forests, indicates some kind of major subsidence, perhaps as the result of an earthquake, must have occurred.'   From Lost Lands and Sunken Cities

Large tracts of coastal land have vanished from mainland Britain over the last two thousand years.

'Ptolemy's map of the British Isles, for instance, whilst considerably inaccurate for the coast of Scotland, tallies reasonably well with the rest of the country, and has the added bonus of possessing a record of longitudes and latitudes for important promontories. Anglesey, which in Roman times was separated from the mainland only by a fordable creek. Cornwall, too, is shown considerably larger than at present

It is recorded that as late as the fourth century, the Scillys, now an archipelago of many islets, was but a single large island. The Scillys.. "were once connected by the now submerged sea-bed to Cornwall." - Snyder - Sub-Roman Britain.  In the year 387 Emperor Maximus exiled two Priscillianist heretics to Scilly.

"Celestial phenomena appear the same pretty much the world over, with a few exceptions. But, if a man in fifth century China saw a comet, chances are good people in fifth century Britain saw it, too. These astronomical records include, around the fifth century, mention of "dragons" coming out of the heavens and smashing into the earth. At about the same time, the Anglo-Saxon Chronicle records how the sun was "dimmed," or how the "stars showed fully nearly half an hour past nine in the morning." At about the same time, tree ring samples from Ireland show that their growth was stunted about the fifth century AD, possibly from lack of sunlight. Saint Patrick, who lived at about the same time, spoke of apocalyptic weather patterns "  - 

In "The Age of Arthur," John Morris notes, "There is ample evidence for a drastic change in sea level of Europe and the Mediterranean towards the end of the Roman Empire; its severity affected the coast and rivers of southern and eastern Britain."

'Many records are also preserved in a curious compilation, published in 1749 by Dr. Thomas Short, F.R.S. Titled 'A General Chronological History of The Air, Meteors, Weather, Seasons, etc., the treatise compiled during sixteen years of research, lists many strange and extreme events. Among them are the great earthquakes of Wales in AD 394, which 'made sad havoc', and the Cornish earthquake of AD 424, where there were 'great losses, many killed'.

related pages

St. Michael Lines

Atlantis, the Lost Land